The electronic health record (E.H.R.) is a cornerstone of improved safety and quality of health care. Many of the benefits from an EHR involve a computerized decision support system (CDSS). While significant research has been conducted on CDSSs, gaps remain. Little research has addressed CDSS in pediatrics and the added value of CDSS has yet to be quantified. This information is important for making decisions regarding value and trade-offs of specific functionalities within an E.H.R. We propose systematic assessment of the improvements in patient safety and experience of care associated with the implementation of four embedded CDSS functions in pediatric practices. In controlled trials and taking advantage of a set of natural experiments, the applicant will assess changes in adverse drug events and patient reports of care experience associated with the implementation of a CDSS in a large integrated delivery system. The four CDSS aids include: 1) weight-based dosing; 2) diagnosis-based medication choice prompts; 3) test result tracking; and 4) reminders for guideline adherence in children with chronic conditions. Specific aims include assessment of: 1) the influence of weight based dosing on pediatric adverse drug events; 2) the influence of a test result tracking system on appropriate follow-up of ordered tests; 3) the influence of automated reminders on symptom monitoring and medications for children with asthma and attention deficit disorder. The applicant will assess changes in patient experience of care using a modified pediatric CAHPS survey. As pediatricians increasingly adopt E.H.R.s, they will be faced with making decisions about the value of specific types of decision support. They will base their decisions on evidence of the effect of the decision support on patient safety, service delivery, physician work, and patient's experience of care. The proposed research will provide quantitative information on the value of CDSS in terms of patient safety, adherence to guidelines, and patient experience of care.